GM 'o7classic LBZ dsl 6 spd to '21 L5P dsl 10 spd report

You will love the B&W. Once you are comfortable with it you can skip the pull test and do a simple "visual test".

PinBox and hitch plates touching, handle closed and locked with jaws closed around the kingpin you are good to go. Of course this is a personal decision.

I would be very concerned with 4.5" of bed clearance. Time to do a little fabricating on the RV's suspension.

If you don't have one get B&W's 1/8" slip plate as it will make unhitching easier.